Re: [PATCH v6 05/45] drm/amd: Add a new helper for loading/validating microcode

["Lazar, Lijo" <lijo.lazar@amd.com>]

On 1/5/2023 10:53 AM, Mario Limonciello wrote:
> On 1/4/23 23:07, Lazar, Lijo wrote:
>>
>>
>> On 1/5/2023 9:12 AM, Mario Limonciello wrote:
>>> All microcode runs a basic validation after it's been loaded. Each
>>> IP block as part of init will run both.
>>>
>>> Introduce a wrapper for request_firmware and amdgpu_ucode_validate.
>>> This wrapper will also remap any error codes from request_firmware
>>> to -ENODEV.  This is so that early_init will fail if firmware couldn't
>>> be loaded instead of the IP block being disabled.
>>>
>>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
>>> ---
>>> v5->v6:
>>>   * Fix argument to be ** not *
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.c | 36 +++++++++++++++++++++++
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.h |  3 ++
>>>   2 files changed, 39 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.c 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.c
>>> index eafcddce58d3..8ebfec12da87 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.c
>>> @@ -1312,3 +1312,39 @@ void amdgpu_ucode_ip_version_decode(struct 
>>> amdgpu_device *adev, int block_type,
>>>       snprintf(ucode_prefix, len, "%s_%d_%d_%d", ip_name, maj, min, 
>>> rev);
>>>   }
>>> +
>>> +/*
>>> + * amdgpu_ucode_request - Fetch and validate amdgpu microcode
>>> + *
>>> + * @adev: amdgpu device
>>> + * @fw: pointer to load firmware to
>>> + * @fw_name: firmware to load
>>> + *
>>> + * This is a helper that will use request_firmware and 
>>> amdgpu_ucode_validate
>>> + * to load and run basic validation on firmware. If the load fails, 
>>> remap
>>> + * the error code to -ENODEV, so that early_init functions will fail 
>>> to load.
>>> + */
>>> +int amdgpu_ucode_request(struct amdgpu_device *adev, const struct 
>>> firmware **fw,
>>> +             const char *fw_name)
>>> +{
>>> +    int err = request_firmware(fw, fw_name, adev->dev);
>>> +
>>> +    if (err)
>>> +        return -ENODEV;
>>> +    err = amdgpu_ucode_validate(*fw);
>>> +    if (err)
>>> +        dev_dbg(adev->dev, "\"%s\" failed to validate\n", fw_name);
>>> +
>>
>> Missed this earlier. If validate fails, shouldn't this undo the 
>> request operation by calling release?
> 
> Actually that was original design, but there is one place in the 
> codebase that expects that ucode validation can fail, and so leave the 
> evaluate of error code and cleanup outside of helper.
> 

I see. Does request_firmware assure that fw pointer be always NULL if it 
fails? Or should that be done here if request_ fails? In subsequent 
patches, I see clients calling release without checking what caused the 
failure.

Thanks,
Lijo

>>
>> Thanks,
>> Lijo
>>
>>> +    return err;
>>> +}
>>> +
>>> +/*
>>> + * amdgpu_ucode_release - Release firmware microcode
>>> + *
>>> + * @fw: pointer to firmware to release
>>> + */
>>> +void amdgpu_ucode_release(const struct firmware **fw)
>>> +{
>>> +    release_firmware(*fw);
>>> +    *fw = NULL;
>>> +}
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.h 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.h
>>> index 552e06929229..848579d4988b 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.h
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ucode.h
>>> @@ -544,6 +544,9 @@ void amdgpu_ucode_print_sdma_hdr(const struct 
>>> common_firmware_header *hdr);
>>>   void amdgpu_ucode_print_psp_hdr(const struct common_firmware_header 
>>> *hdr);
>>>   void amdgpu_ucode_print_gpu_info_hdr(const struct 
>>> common_firmware_header *hdr);
>>>   int amdgpu_ucode_validate(const struct firmware *fw);
>>> +int amdgpu_ucode_request(struct amdgpu_device *adev, const struct 
>>> firmware **fw,
>>> +             const char *fw_name);
>>> +void amdgpu_ucode_release(const struct firmware **fw);
>>>   bool amdgpu_ucode_hdr_version(union amdgpu_firmware_header *hdr,
>>>                   uint16_t hdr_major, uint16_t hdr_minor);
>